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| author | Lukas Wunner <lukas@wunner.de> | 2018-11-29 16:45:24 +0100 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2018-12-04 16:51:55 +0000 |
| commit | 2527704d8411e2b4241916e8b22505cb4519ce08 (patch) | |
| tree | 8214b5bc0e342dc11a046b41a5f06e74d2416833 /drivers | |
| parent | 2e0733bc5a15a33f72ec2c323915f72cc65d8960 (diff) | |
| download | lwn-2527704d8411e2b4241916e8b22505cb4519ce08.tar.gz lwn-2527704d8411e2b4241916e8b22505cb4519ce08.zip | |
spi: bcm2835: Synchronize with callback on DMA termination
Commit b36f09c3c441 ("dmaengine: Add transfer termination
synchronization support") deprecated dmaengine_terminate_all() in favor
of dmaengine_terminate_sync() and dmaengine_terminate_async() to avoid
freeing resources used by the DMA callback before its execution has
concluded.
Commit de92436ac40f ("dmaengine: bcm2835-dma: Use vchan_terminate_vdesc()
instead of desc_free") amended the BCM2835 DMA driver with an
implementation of ->device_synchronize(), which is a prerequisite for
dmaengine_terminate_sync(). Thus, clients of the DMA driver (such as
the BCM2835 SPI driver) may now be converted to the new API.
It is generally desirable to use the _sync() variant except in atomic
context. There is only a single occurrence where the BCM2835 SPI driver
calls dmaengine_terminate_all() in atomic context and that is in
bcm2835_spi_dma_done() (the RX DMA channel's callback) to terminate the
TX DMA channel. The TX DMA channel doesn't have a callback (yet), hence
it is safe to use the _async() variant there.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/spi/spi-bcm2835.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 5af4cf74392c..35aebdfd3b4e 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -514,7 +514,7 @@ static void bcm2835_spi_dma_done(void *data) * situation otherwise... */ if (cmpxchg(&bs->dma_pending, true, false)) { - dmaengine_terminate_all(master->dma_tx); + dmaengine_terminate_async(master->dma_tx); bcm2835_spi_undo_prologue(bs); } @@ -605,7 +605,7 @@ static int bcm2835_spi_transfer_one_dma(struct spi_master *master, ret = bcm2835_spi_prepare_sg(master, tfr, false); if (ret) { /* need to reset on errors */ - dmaengine_terminate_all(master->dma_tx); + dmaengine_terminate_sync(master->dma_tx); bs->dma_pending = false; goto err_reset_hw; } @@ -650,12 +650,12 @@ static bool bcm2835_spi_can_dma(struct spi_master *master, static void bcm2835_dma_release(struct spi_master *master) { if (master->dma_tx) { - dmaengine_terminate_all(master->dma_tx); + dmaengine_terminate_sync(master->dma_tx); dma_release_channel(master->dma_tx); master->dma_tx = NULL; } if (master->dma_rx) { - dmaengine_terminate_all(master->dma_rx); + dmaengine_terminate_sync(master->dma_rx); dma_release_channel(master->dma_rx); master->dma_rx = NULL; } @@ -864,8 +864,8 @@ static void bcm2835_spi_handle_err(struct spi_master *master, /* if an error occurred and we have an active dma, then terminate */ if (cmpxchg(&bs->dma_pending, true, false)) { - dmaengine_terminate_all(master->dma_tx); - dmaengine_terminate_all(master->dma_rx); + dmaengine_terminate_sync(master->dma_tx); + dmaengine_terminate_sync(master->dma_rx); bcm2835_spi_undo_prologue(bs); } /* and reset */ |